Optical coherence tomographic comparison of naive macular edema due to ischemic and nonischemic retinal vein occlusion.

Abstract

To examine the macular microstructure in macular edema (ME) due to retinal vein occlusion (RVO) in terms of ischemic or nonischemic type to determine whether and how ischemia affects macular microstructure. This retrospective, nonrandomized study included 75 newly diagnosed RVO cases (group 1: 55 nonischemic RVO cases and group 2: 20 ischemic RVO cases) with evidence of center-involving ME without any treatment. Quantitative measures on spectral-domain optical coherence tomography images were performed. Central subfield thickness (CST) was collected in the central 1mm from the thickness map. The following items were evaluated in a 3-mm-wide area (perifoveal ETDRS circle) centered on the fovea: disorganization of the retinal inner layers (DRIL), disrupted external limiting membrane (ELM) and ellipsoid zone disruption (EZD). The microstructural changes were measured manually. Baseline characteristics, such as age, sex, study eye, and RVO risk factors, were similar between the groups (P > 0.05). CST was 554.15 ± 191.45µm for group 1 and 769.90 ± 290.00µm for group 2 (P: 0.001). The extent of DRIL was 1864.09 ± 941.70µm and 2447.25 ± 492.59µm for groups 1 and 2, respectively (P: 0.010). The disrupted ELM length was 1700 (0-3000) µm for group 1 and 2725 (300-3000) µm for group 2 (P: 0.027). The EZD length was 1453.09 ± 870.38µm for group 1 and 1846.00 ± 926.54µm for group 2 (P: 0.093). Ischemic RVOs cause greater macular edema and greater disruption in the macular microstructure compared to nonischemic RVOs, especially in terms of DRIL and ELM.